A kind of high polarity hot melt adhesive and preparation method thereof

Abstract

The present invention discloses a high-polarity hot melt adhesive and a preparation method thereof, and relates to the field of adhesives. Wherein, the high-polarity hot melt adhesive is made of 15-20wt% rosin pentaerythritol ester, 4.5-6.5wt% terpene phenolic resin, 2-4wt% polystyrene modified rosin resin, 5-10wt% liquid rosin resin, 3-5wt% SIS rubber, 5.5-8.5wt% maleic anhydride modified EVA resin, 7.5-10wt% wax, 1-2wt% antioxidant and surplus EVA resin. The present application obtains a high-polarity hot melt adhesive having quick-drying property, high bonding strength, strong versatility to substrates, low temperature resistance and weather resistance by the coordination of a specific proportion of rosin pentaerythritol ester, terpene phenolic resin, polystyrene modified rosin resin, liquid rosin resin, SIS rubber, maleic anhydride modified EVA resin, wax, antioxidant and EVA resin.

Description

Technical Field

[0001] The present application relates to the field of adhesives, and in particular to a high-polarity hot melt adhesive and a preparation method thereof. Background Art

[0002] In the field of adhesives, hot melt adhesives are widely used due to their advantages of no need for solvents, no pollution, and rapid curing. At present, the commonly used hot melt adhesives are ethylene-vinyl acetate (EVA) hot melt adhesives and polyolefin system (PO) hot melt adhesives. Compared with polyolefin hot melt adhesives, EVA hot melt adhesives can be combined with high polarity resins and have better bonding performance to polar materials.

[0003] Among them, EVA hot melt adhesive is usually made of EVA resin, rosin pentaerythritol ester, rosin glycerol ester, petroleum resin, and antioxidant. Among them, EVA resin is used as a base resin material, rosin pentaerythritol ester, rosin glycerol ester and petroleum resin are used as tackifying resins, and antioxidants are used as thermal stabilizers. The EVA hot melt adhesive has good bonding strength to polar substrates such as paper and wood, but has poor bonding strength to low-polarity substrates such as PP and PE. In addition, people have higher and higher requirements for the quick-drying, weather resistance and low-temperature resistance of hot melt adhesives. How to effectively improve the versatility, quick-drying, weather resistance and low-temperature resistance of hot melt adhesives to substrates has also become a key research issue at present. Summary of the invention

[0004] In order to improve the applicability of EVA hot melt adhesive to substrates in the related art while improving the quick-drying property, weather resistance and low temperature resistance of the hot melt adhesive, the present application provides a high-polarity hot melt adhesive and a preparation method thereof.

[0005] In the first aspect, the present application provides a high polarity hot melt adhesive using the following technical solution:

[0006] A high-polarity hot melt adhesive is prepared from 15-20wt% of rosin pentaerythritol ester, 4.5-6.5wt% of terpene phenolic resin, 2-4wt% of polystyrene modified rosin resin, 5-10wt% of liquid rosin resin, 3-5wt% of SIS rubber, 5.5-8.5wt% of maleic anhydride modified EVA resin, 7.5-10wt% of wax, 1-2wt% of antioxidant and the remainder of EVA resin.

[0007] The present application adopts rosin pentaerythritol ester, terpene phenolic resin, polystyrene modified rosin resin, and liquid rosin resin as tackifying resins, wherein rosin pentaerythritol ester is the main component of tackifying resin, and has good wetting and permeability to the substrate; adding terpene phenolic resin containing both terpene hydrocarbon structure and phenolic aromatic structure helps to improve the quick-drying performance of hot melt adhesive, and can provide good thermal stability and cross-linking ability, which helps to improve the cohesion of hot melt adhesive, enhance the bonding strength between hot melt adhesive and substrate, and improve the weather resistance of hot melt adhesive. Polystyrene modified rosin resin has good compatibility with EVA resin, can be evenly dispersed in EVA resin, and improves the quick-drying performance and weather resistance of hot melt adhesive. Liquid rosin resin can adjust the fluidity of the system, and contains polar carboxyl groups, which can improve the quick-drying performance and bonding strength of hot melt adhesive, and at the same time improve the low temperature resistance of hot melt adhesive. When rosin pentaerythritol ester, terpene phenolic resin, polystyrene modified rosin resin and liquid rosin resin within the above-mentioned proportion range are used together as tackifying resins, it is beneficial to obtain a hot melt adhesive with quick drying, high bonding strength and weather resistance. The hot melt adhesive has strong polarity, good fluidity and wetting permeability, and has excellent bonding strength to both polar and non-polar substrates, that is, it has strong versatility to substrates.

[0008] The addition of SIS rubber can improve the quick-drying performance of hot melt adhesive, and the combination of SIS rubber and liquid rosin resin can further improve the low-temperature resistance of hot melt adhesive. However, the proportion of SIS rubber should not exceed 5wt%, otherwise it will reduce the weather resistance of hot melt adhesive.

[0009] The addition of maleic anhydride modified EVA resin can increase the polarity of the hot melt adhesive, thereby further improving the bonding strength of the hot melt adhesive to the substrate.

[0010] The addition of wax can reduce the melt viscosity and improve the heat resistance to a certain extent, but wax has the effect of a demolding agent. Too high a proportion will affect the bonding strength of the hot melt adhesive to the substrate.

[0011] In summary, the high-polarity hot melt adhesive in the present application is made of a specific proportion of rosin pentaerythritol ester, terpene phenolic resin, polystyrene modified rosin resin, liquid rosin resin, SIS rubber, maleic anhydride modified EVA resin, wax, antioxidant and EVA resin. It is a high-polarity hot melt adhesive with fast drying, high bonding strength, strong versatility to substrates, low temperature resistance and weather resistance.

[0012] Preferably, the terpene phenolic resin has a softening point of 120-130° C. and an acid value of 25-30 mgKOH / g.

[0013] In the present application, the terpene phenolic resin preferably has a softening point of 120-130°C and an acid value of 25-30 mgKOH / g, which is conducive to obtaining a hot melt adhesive with both melt fluidity and viscosity, and can further improve the quick-drying performance of the hot melt adhesive while ensuring high adhesion and weather resistance of the hot melt adhesive.

[0014] Optionally, the preparation method of the polystyrene modified rosin resin is as follows:

[0015] 25.8-32.6 parts by weight of polystyrene, 67.4-74.2 parts by weight of rosin pentaerythritol ester and 1-2 parts by weight of peroxide initiator are melt-mixed at 125-135° C. to obtain a polystyrene modified rosin resin.

[0016] In the present application, the polystyrene-modified rosin resin is preferably a polystyrene-modified rosin resin obtained by melt-mixing polystyrene and rosin pentaerythritol ester within the above-mentioned ratio range at 125-135°C. The polystyrene-modified rosin resin has good compatibility with other raw materials, which is conducive to further improving the quick-drying performance and weather resistance of the hot melt adhesive. Among them, when the polystyrene content is too high or too low, and the melt mixing temperature of polystyrene and rosin resin is not within the above-mentioned range, the quick-drying performance and weather resistance of the hot melt adhesive are both reduced due to the influence of the structure of the polystyrene-modified rosin resin or the compatibility of the polystyrene-modified rosin resin with other raw materials.

[0017] Optionally, the acid value of the liquid rosin resin is 8-16 mgKOH / g.

[0018] In the present application, the acid value of the liquid rosin resin is 8-16 mgKOH / g, which can further improve the quick-drying performance of the hot melt adhesive. At the same time, the bonding strength of the hot melt adhesive to the substrate will not be adversely affected.

[0019] Preferably, in the SIS rubber, the block ratio S / I is (15-20) / (80-85), and the melt index of the SIS rubber is 10-20 g / 10 min (200° C. / 5 kg).

[0020] In the present application, when the SIS rubber block ratio S / I is controlled within the range of (15-20) / (80-85) and the melt index of the SIS rubber measured at a temperature of 200°C and a load of 5kg is 10-20g / 10min, it is beneficial to further improve the low temperature resistance of the hot melt adhesive while maintaining the quick drying property of the hot melt adhesive.

[0021] Optionally, in the maleic anhydride modified EVA resin, the grafting rate of maleic anhydride is 6000-7000 ppm, and the melt index of the maleic anhydride modified EVA resin is 150-210 g / 10 min (190° C. / 2.16 kg).

[0022] In the present application, the grafting rate of the maleic anhydride modified EVA resin is 6000-7000ppm, and the melt index measured at a temperature of 190°C and a load of 2.16kg is 150-210g / 10min, which is conducive to the full fusion of the maleic anhydride modified EVA resin with other raw materials, further improves the polarity of the hot melt adhesive, and further improves the bonding strength to the substrate.

[0023] Preferably, the wax comprises EVA wax and maleic anhydride modified polyethylene wax, and the weight ratio of the EVA wax to the maleic anhydride modified polyethylene wax is 1:(1-1.5).

[0024] In the present application, the wax adopts a composition of EVA wax and maleic anhydride modified polyethylene wax in a weight ratio of 1: (1-1.5), wherein the addition of EVA wax can further improve the low temperature resistance of the hot melt adhesive, and maleic anhydride modified polyethylene wax has the characteristics of high polarity and high melting point, which can further improve the bonding strength and weather resistance of the hot melt adhesive to the substrate. In addition, by controlling the ratio of EVA wax and maleic anhydride modified polyethylene wax, the hot melt adhesive can further improve its bonding performance to the substrate, low temperature resistance and weather resistance without affecting the quick drying performance of the hot melt adhesive.

[0025] Optionally, the content of vinyl acetate in the EVA resin is 18-45%.

[0026] Further preferably, the content of vinyl acetate in the EVA resin is 25-35%.

[0027] Optionally, the antioxidant is at least one of 1010 and antioxidant 168.

[0028] In the second aspect, the present application provides a method for preparing a high-polarity hot melt adhesive using the following technical solution:

[0029] A method for preparing a high-polarity hot melt adhesive comprises the following steps:

[0030] Putting the antioxidant and wax into a reaction vessel at a temperature of 160-180° C. and melting them uniformly to obtain a first mixture;

[0031] The temperature of the reaction container is lowered to 140-150° C., and the temperature of the reaction container is maintained unchanged. Then, SIS rubber and part of EVA resin are added to the first mixture, and stirred until the SIS rubber is completely swollen into a transparent state, thereby obtaining a second mixture;

[0032] Continue to maintain the temperature of the reaction container at 140-150° C., add the maleic anhydride-modified EVA resin and the remaining EVA resin to the second mixture, and stir until the mixture is uniformly melted to obtain a third mixture;

[0033] Continue to maintain the temperature of the reaction container at 140-150° C., add rosin-enhanced pentaerythritol ester, terpene phenolic resin, polystyrene-modified rosin resin and liquid rosin resin to the third mixture, stir until it is uniformly melted to obtain a fourth mixture; extrude, granulate and perform anti-sticking treatment on the fourth mixture to obtain a hot melt adhesive suitable for polar substrates.

[0034] The present application adopts the above method to prepare high-polarity hot melt adhesive, which ensures that all components are fully fused and the temperature is reasonably controlled, avoiding decomposition of raw materials due to excessively high temperature and uneven mixing of raw materials due to excessively low temperature, thereby achieving uniform mixing and effective reaction between the raw materials, and further improving the comprehensive performance of the hot melt adhesive.

[0035] Among them, in the step of adding SIS rubber, the weight ratio of SIS rubber to EVA resin is (2.5-3.5):1, which is conducive to the uniform melting of SIS rubber.

[0036] In summary, this application at least includes the following beneficial technical effects:

[0037] 1. The present application obtains a high-polarity hot melt adhesive with quick drying, high bonding strength, strong versatility to substrates, low temperature resistance and weather resistance by combining specific proportions of rosin pentaerythritol ester, terpene phenolic resin, polystyrene modified rosin resin, liquid rosin resin, SIS rubber, maleic anhydride modified EVA resin, wax, antioxidant and EVA resin.

[0038] 2. This application adopts the above method to prepare high-polarity hot melt adhesive, which ensures that all components are fully fused and the temperature is reasonably controlled, avoiding decomposition of raw materials due to excessively high temperature and uneven mixing of raw materials due to excessively low temperature, thereby achieving uniform mixing and effective reaction between the raw materials, and further improving the comprehensive performance of the hot melt adhesive. DETAILED DESCRIPTION

[0039] The present application is further described below in conjunction with specific experiments.

[0040] Example

[0041] [Example 1]

[0042] A high-polarity hot melt adhesive is prepared from 15kg of rosin pentaerythritol ester, 6.5kg of terpene phenolic resin, 2kg of polystyrene modified rosin resin, 5kg of liquid rosin resin, 3kg of SIS rubber, 8.5kg of maleic anhydride modified EVA resin, 7.5kg of wax, 1kg of antioxidant and 51.5kg of EVA resin.

[0043] In this embodiment, the rosin pentaerythritol ester specifically adopts 145 rosin pentaerythritol ester.

[0044] The terpene phenolic resin specifically adopts terpene phenolic resin DA-23, and the softening point of terpene phenolic resin DA-23 is 145-155° C., and the hydroxyl value is 45-55 mgKOH / g.

[0045] The polystyrene modified rosin resin was prepared by melt mixing 25.8 kg of polystyrene 143E GPPS, 67.4 kg of 145 rosin pentaerythritol ester, and 1 kg of dibenzoyl peroxide at 125° C. for 2.5 hours to obtain the polystyrene modified rosin resin.

[0046] The liquid rosin resin specifically adopts SJ-30 liquid resin, and the acid value is 8-16 mgKOH / g.

[0047] The SIS rubber specifically adopts SIS rubber with a grade of 1209 produced by Baling Petrochemical, in which S / I=29 / 71 and the melt index of the SIS rubber is 10 g / 10 min (200° C., 5 kg).

[0048] The maleic anhydride modified EVA resin is Orevac T9305, the grafting rate of maleic anhydride is 6400ppm, and the melt index is 150-210g / 10min (190°C, 2.16kg).

[0049] The wax is EVA3 wax with a dropping point of 99-108°C.

[0050] Specifically, antioxidant 1010 is used as the antioxidant.

[0051] The EVA resin used was Dow 220W, the vinyl acetate content was 28%, and the melt index was 150 g / 10 min (190° C., 2.16 kg).

[0052] In this embodiment, the preparation method of the high polarity hot melt adhesive comprises the following steps:

[0053] Putting an antioxidant and wax into a reaction vessel at a temperature of 160° C. and melting them uniformly to obtain a first mixture;

[0054] The temperature of the reaction container is lowered to 150° C., and the temperature of the reaction container is maintained unchanged. Then, SIS rubber and part of EVA resin are added to the first mixture. In this step, SIS rubber and EVA resin are added in a weight ratio of 3:1, and stirred until the SIS rubber is completely swollen into a transparent state, thereby obtaining a second mixture.

[0055] The temperature of the reaction container is kept at 140° C., and the maleic anhydride-modified EVA resin and the remaining EVA resin are added to the second mixture, and stirred until the mixture is uniformly melted to obtain a third mixture;

[0056] The temperature of the reaction container is kept at 140° C., and rosin pentaerythritol ester, terpene phenolic resin, polystyrene modified rosin resin and liquid rosin resin are added to the third mixture, and stirred until the mixture is uniformly melted to obtain a fourth mixture;

[0057] The fourth mixture is extruded, granulated, and subjected to anti-sticking treatment to obtain a high-polarity hot melt adhesive.

[0058] [Example 2]

[0059] A high-polarity hot melt adhesive is prepared from 20kg of rosin pentaerythritol ester, 4.5kg of terpene phenolic resin, 4kg of polystyrene modified rosin resin, 10kg of liquid rosin resin, 5kg of SIS rubber, 5.5kg of maleic anhydride modified EVA resin, 10kg of wax, 2kg of antioxidant and 39kg of EVA resin.

[0060] In this embodiment, the rosin pentaerythritol ester specifically adopts 145 rosin pentaerythritol ester.

[0061] The terpene phenolic resin specifically adopts terpene phenolic resin DA-23, and the softening point of terpene phenolic resin DA-23 is 145-155° C., and the hydroxyl value is 45-55 mgKOH / g.

[0062] The polystyrene modified rosin resin was prepared by melt mixing 32.6 kg of polystyrene 143E GPPS, 74.2 kg of 145 rosin pentaerythritol ester, and 2 kg of dibenzoyl peroxide at 135° C. for 2 h to obtain the polystyrene modified rosin resin.

[0063] The liquid rosin resin specifically adopts SJ-30 liquid resin, and the acid value is 8-16 mgKOH / g.

[0064] The SIS rubber specifically adopts SIS rubber with a grade of 1125 produced by Baling Petrochemical, in which S / I=25 / 75 and the melt index of the SIS rubber is 9 g / 10 min (200° C., 5 kg).

[0065] The maleic anhydride modified EVA resin is Orevac T9305, the grafting rate of maleic anhydride is 6400ppm, and the melt index is 150-210g / 10min (190°C, 2.16kg).

[0066] The wax is EVA3 wax with a dropping point of 99-108°C.

[0067] The antioxidant is specifically a combination of antioxidant 1010 and antioxidant 168, and the weight ratio of antioxidant 1010 to antioxidant 168 is 2:1.

[0068] The EVA resin used was Dow 220W, the vinyl acetate content was 28%, and the melt index was 150 g / 10 min (190° C., 2.16 kg).

[0069] In this embodiment, the preparation method of the high polarity hot melt adhesive comprises the following steps:

[0070] Putting the antioxidant and wax into a reaction vessel at a temperature of 180° C. and melting them uniformly to obtain a first mixture;

[0071] The temperature of the reaction container is lowered to 140° C., and the temperature of the reaction container is maintained unchanged. Then, SIS rubber and part of EVA resin are added to the first mixture. In this step, SIS rubber and EVA resin are added in a weight ratio of 3:1, and stirred until the SIS rubber is completely swollen into a transparent state, thereby obtaining a second mixture.

[0072] The temperature of the reaction container is kept at 150° C., and the maleic anhydride-modified EVA resin and the remaining EVA resin are added to the second mixture, and stirred until the mixture is uniformly melted to obtain a third mixture;

[0073] The temperature of the reaction container is kept at 150° C., and rosin pentaerythritol ester, terpene phenolic resin, polystyrene modified rosin resin and liquid rosin resin are added to the third mixture, and stirred until the mixture is uniformly melted to obtain a fourth mixture;

[0074] The fourth mixture is extruded, granulated, and subjected to anti-sticking treatment to obtain a high-polarity hot melt adhesive.

[0075] [Example 3]

[0076] A high polarity hot melt adhesive, which differs from [Example 1] in that the terpene phenolic resin is different.

[0077] In this embodiment, the terpene phenolic resin specifically adopts terpene phenolic resin DA-21 and terpene phenolic resin DA-23, the softening point of which is 120-130° C. and the hydroxyl value is 25-30 mgKOH / g.

[0078] [Example 4]

[0079] A high polarity hot melt adhesive, which differs from [Example 3] in that the polystyrene modified rosin resin is different.

[0080] In this embodiment, the polystyrene modified rosin resin is prepared by melt mixing 38 kg of polystyrene 143E GPPS, 62 kg of 145 rosin pentaerythritol ester, and 2 kg of dibenzoyl peroxide at 150° C. for 2 hours to obtain the polystyrene modified rosin resin.

[0081] [Example 5]

[0082] A high polarity hot melt adhesive, which differs from [Example 3] in that the SIS rubber is different.

[0083] In this embodiment, the SIS rubber is specifically SIS rubber with a grade of 1105 produced by Baling Petrochemical, in which S / I=15 / 85, and the melt index of the SIS rubber is 10g / 10min (200°C, 5kg).

[0084] [Example 6]

[0085] A high polarity hot melt adhesive, which differs from [Example 3] in that the wax is different.

[0086] In this embodiment, the wax is a composition of EVA3 wax and maleic anhydride modified polyethylene wax Licocene PE MA4351, and the weight ratio of EVA3 wax to maleic anhydride modified polyethylene wax Licocene PE MA4351 is 1:1.

[0087] Comparative Example

[0088] [Comparative Example 1]

[0089] A hot melt adhesive, which differs from [Example 1] in that:

[0090] In this comparative example, the terpene phenolic resin is replaced by an equal amount of rosin pentaerythritol ester.

[0091] [Comparative Example 2]

[0092] A hot melt adhesive, which differs from [Example 1] in that:

[0093] In this comparative example, the polystyrene modified rosin resin is replaced by an equal amount of rosin pentaerythritol ester.

[0094] [Comparative Example 3]

[0095] A hot melt adhesive, which differs from [Example 1] in that:

[0096] In this comparative example, the liquid rosin resin was replaced by an equal amount of rosin pentaerythritol ester.

[0097] [Comparative Example 4]

[0098] In this comparative example, SIS rubber is replaced by an equal amount of EVA resin.

[0099] [Comparative Example 5]

[0100] A hot melt adhesive, which is different from [Example 1] in that the amounts of each component are different.

[0101] In this comparative example, it is prepared from 15 kg of rosin pentaerythritol ester, 1.5 kg of terpene phenolic resin, 7 kg of polystyrene modified rosin resin, 15 kg of liquid rosin resin, 3 kg of SIS rubber, 4.5 kg of maleic anhydride modified EVA resin, 11.5 kg of wax, 1 kg of antioxidant and 41.5 kg of EVA resin.

[0102] [Comparative Example 6]

[0103] A hot melt adhesive, which is different from [Example 1] in that the amounts of each component are different.

[0104] In this comparative example, it is prepared from 25 kg of rosin pentaerythritol ester, 8 kg of terpene phenolic resin, 0.5 kg of polystyrene modified rosin resin, 5 kg of liquid rosin resin, 8 kg of SIS rubber, 3.5 kg of maleic anhydride modified EVA resin, 7.5 kg of wax, 1 kg of antioxidant and 41.5 kg of EVA resin.

[0105] Performance testing

[0106] (1) Open time test method: The hot melt adhesives in the embodiments and comparative examples were tested with reference to HG / T 3716-2003 Determination of open time of hot melt adhesives. The test was conducted in an environment with a temperature of 23°C ± 2°C and a relative humidity of 50% ± 5%. The hot melt adhesive melt temperature was 150°C ± 2°C, and the test interval was 5s. The open time of different hot melt adhesives is recorded in Table 1. The shorter the open time, the better the quick-drying property of the hot melt adhesive.

[0107] (2) Tensile shear strength test method: The hot melt adhesives in the embodiments and comparative examples were used for bonding wood boards and PE boards to prepare two groups of samples. The tensile shear strength between different hot melt adhesives and different substrates in the two groups of samples was tested with reference to GB / T 7124-2008 "Determination of tensile shear strength of adhesives (rigid material to rigid material)", with a tensile rate of 10 mm / min. The results are recorded in Table 2. The higher the tensile shear strength, the higher the bonding strength of the hot melt adhesive to the substrate, and the better the bonding performance.

[0108] (3) Weather resistance test method: The sample in test (2) was heated to 80°C and kept at this temperature for 500 h. The tensile shear strength was tested in accordance with GB / T7124-2008 "Determination of tensile shear strength of adhesives (rigid material to rigid material)" at a tensile rate of 10 mm / min. The results are recorded in Table 2. The smaller the decrease in tensile shear strength before and after high temperature treatment, the better the weather resistance of the hot melt adhesive.

[0109] (4) Low temperature resistance test method: The hot melt adhesives in the embodiments and comparative examples were made into thin hot melt adhesive sheets with a size of 75 mm*10 mm*1.25 mm (length*width*height). In an environment of -10°C, the thin hot melt adhesive sheets in the embodiments and comparative examples were subjected to bending tests on mandrels with diameters of 12.8 mm, 6.4 mm, and 3.2 mm, respectively, with reference to HG / T 4222-2011 hot melt adhesive low temperature flexibility test method. The mandrel with the smallest diameter through which four out of five samples passed was recorded as the flexibility of the hot melt adhesive. The smaller the smallest mandrel diameter, the better the low temperature resistance of the hot melt adhesive.

[0110] Table 1

[0111] Sample Opening hours / s Example 1 15 Example 2 10 Example 3 10 Example 4 15 Example 5 5 Example 6 10 Comparative Example 1 20 Comparative Example 2 25 Comparative Example 3 25 Comparative Example 4 15 Comparative Example 5 15 Comparative Example 6 15

[0112] Table 2

[0113]

[0114]

[0115] Table 3

[0116] Sample Minimum mandrel diameter / mm Example 1 6.4 Example 2 6.4 Example 3 6.4 Example 4 6.4 Example 5 3.2 Example 6 3.2 Comparative Example 1 6.4 Comparative Example 2 6.4 Comparative Example 3 12.8 Comparative Example 4 12.8 Comparative Example 5 3.2 Comparative Example 6 3.2

[0117] Combining Example 1 with Comparative Examples 1-4 and the data in Tables 1-3, it can be seen that when rosin pentaerythritol ester, terpene phenolic resin, polystyrene modified rosin resin and liquid rosin resin are used together as tackifying resins, it is beneficial to obtain a hot melt adhesive with quick drying, high bonding strength and weather resistance, and the hot melt adhesive has strong polarity, good fluidity and wetting permeability, and has excellent bonding strength to both polar and non-polar substrates. In addition, the combination of SIS rubber and liquid rosin resin is beneficial to improving the low temperature resistance of the hot melt adhesive.

[0118] Combining Example 1 with Comparative Examples 5-6 and the data in Tables 1-3, it can be seen that in the present application, the raw materials used for the hot melt adhesive remain unchanged, and the ratio of each raw material is changed. Although a hot melt adhesive with good quick-drying properties can be obtained, the hot melt adhesive has poor bonding strength to the substrate and poor weather resistance.

[0119] Combining Example 1 and Example 3 and the data in Tables 1-3, it can be seen that in the present application, the terpene phenolic resin preferably has a softening point of 120-130°C and an acid value of 25-30 mgKOH / g, which is conducive to obtaining a hot melt adhesive with both melt fluidity and viscosity, and can further improve the quick-drying performance of the hot melt adhesive while ensuring high adhesion and weather resistance of the hot melt adhesive.

[0120] Combining Example 3 and Example 4 and the data in Table 1-3, it can be seen that the polystyrene-modified rosin resin is preferably a polystyrene-modified rosin resin obtained by melt mixing polystyrene and rosin pentaerythritol ester within the ratio range of the present application in the range of 125-135°C. The polystyrene-modified rosin resin has good compatibility with other raw materials, which is beneficial to further improve the quick-drying performance and weather resistance of the hot melt adhesive.

[0121] Combining Example 3 with Example 5 and the data in Table 1-3, it can be seen that when the SIS rubber block ratio S / I is controlled within the range of (15-20) / (80-85) and the melt index of the SIS rubber measured at a temperature of 200°C and a load of 5 kg is 10-20 g / 10 min, it is beneficial to further improve the low temperature resistance of the hot melt adhesive while maintaining the quick drying property of the hot melt adhesive.

[0122] Combining Example 3 and Example 6 and the data in Table 1-3, it can be seen that the wax in this application adopts a composition of EVA wax and maleic anhydride modified polyethylene wax in a specific ratio, which can further improve the adhesion performance of the hot melt adhesive to the substrate, low temperature resistance and weather resistance without affecting the quick-drying performance of the hot melt adhesive.

[0123] This specific implementation manner is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the specific implementation manner as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A high polarity hot melt adhesive, characterized in that: The invention is prepared from 15-20wt% of rosin pentaerythritol ester, 4.5-6.5wt% of terpene phenolic resin, 2-4wt% of polystyrene modified rosin resin, 5-10wt% of liquid rosin resin, 3-5wt% of SIS rubber, 5.5-8.5wt% of maleic anhydride modified EVA resin, 7.5-10wt% of wax, 1-2wt% of antioxidant and the balance of EVA resin; The preparation method of the polystyrene modified rosin resin is as follows: 25.8-32.6 parts by weight of polystyrene, 67.4-74.2 parts by weight of rosin pentaerythritol ester and 1-2 parts by weight of peroxide initiator are melt-mixed at 125-135° C. to obtain a polystyrene modified rosin resin.

2. A high polarity hot melt adhesive according to claim 1, characterized in that: The terpene phenolic resin has a softening point of 120-130° C. and an acid value of 25-30 mgKOH / g.

3. A high polarity hot melt adhesive according to claim 1, characterized in that: The acid value of the liquid rosin resin is 8-16 mgKOH / g.

4. A high polarity hot melt adhesive according to claim 1, characterized in that: In the SIS rubber, the block ratio S / I is (15-20) / (80-85), and the melt index of the SIS rubber is 10-20 g / 10 min (200° C. / 5 kg).

5. The high polarity hot melt adhesive according to claim 1, characterized in that: In the maleic anhydride modified EVA resin, the grafting rate of maleic anhydride is 6000-7000 ppm, and the melt index of the maleic anhydride modified EVA resin is 150-210 g / 10 min (190° C. / 2.16 kg).

6. A high polarity hot melt adhesive according to claim 1, characterized in that: The wax comprises EVA wax and maleic anhydride modified polyethylene wax, and the weight ratio of the EVA wax to the maleic anhydride modified polyethylene wax is 1:(1-1.5).

7. The high polarity hot melt adhesive according to claim 1, characterized in that: In the EVA resin, the content of vinyl acetate is 18-45%.

8. The high polarity hot melt adhesive according to claim 1, characterized in that: The antioxidant is at least one of 1010 and antioxidant 168.

9. A method for preparing a high-polarity hot melt adhesive according to any one of claims 1 to 8, characterized in that: The following steps are involved: Putting the antioxidant and wax into a reaction vessel at a temperature of 160-180° C. and melting them uniformly to obtain a first mixture; The temperature of the reaction container is lowered to 140-150° C., and the temperature of the reaction container is maintained unchanged. Then, SIS rubber and part of EVA resin are added to the first mixture, and stirred until the SIS rubber is completely swollen into a transparent state, thereby obtaining a second mixture; Continue to maintain the temperature of the reaction container at 140-150° C., add the maleic anhydride-modified EVA resin and the remaining EVA resin to the second mixture, and stir until the mixture is uniformly melted to obtain a third mixture; Continue to maintain the temperature of the reaction container at 140-150° C., add rosin pentaerythritol ester, terpene phenolic resin, polystyrene modified rosin resin and liquid rosin resin to the third mixture, and stir until the mixture is uniformly melted to obtain a fourth mixture; The fourth mixture is extruded, granulated, and subjected to anti-sticking treatment to obtain a high-polarity hot melt adhesive.

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